importing wma files to iTunes

Back when i was a PC user, i copied all the music i love off my CDs onto my PC (don't recall what program I used to do so) and then threw away the CDs. When i converted to Mac, many of these songs didn't import to iTunes. They appear to be .wma files. Since i've already thrown away the CDs, is there any way to keep/play my music in iTunes or am i out of luck? It'll cost me a fortune to re-buy all these songs one at a time.